In semiconductor devices such as Integrated Circuits (IC) or Light Emitting Diodes (LED), performance and device lifetime are influenced by the temperature of the PN junction of the semiconductor die or chip. Management of the temperature of semiconductor devices is therefore of importance in maintaining reliable performance and long term operation. Such thermal management of semiconductor devices is of particular importance in applications with long life requirements, and in applications comprising a number of semiconductor devices.
For instance, in a lighting application, an optical device, for example, a luminaire may comprise an array of light sources such as LEDs. The number of LEDs as well as their proximity to one another leads to a more significant generation of thermal energy. Consequently, managing cooling of the devices becomes more critical for long term, reliable operation.
Various solutions for cooling semiconductor devices have been proposed. For example, WO 2008/037992 describes a thermally managed lamp assembly in which a number of high power LEDs are mounted in a housing. A drawback of the system described in WO 2008/037992 is that heat transfer efficiency is not optimised since the air flow passes from one LED heat sink assembly to another. Furthermore, dust can be drawn into the housing during operation of the device. The presence of this dust can be detrimental to the performance of the LEDs. In one particular construction, each LED is provided with a fan to produce a current of air to cool the respective LED. Such a configuration suffers the drawback that noise generation of the fans creates a generally noisy environment and can be detrimental to the performance of the semiconductor device. Moreover, in view of the number of fans employed, the overall device can be costly and cumbersome.